SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24b5ebc573d26d9cfac8c3e05aca285a5fcfaad8889361269c2c13e40644ff3a' 
  AND token = '5YkYryCWwTxjpYI/sh/6vPjEOkDIHklFE2R8UbOSgYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}